2121111211221 has 24 divisors (see below), whose sum is σ = 3150632101344. Its totient is φ = 1374107522400.

The previous prime is 2121111211213. The next prime is 2121111211273. The reversal of 2121111211221 is 1221121111212.

It is a happy number.

2121111211221 is a `hidden beast` number, since 2 + 121 + 111 + 211 + 221 = 666.

It is not a de Polignac number, because 2121111211221 - 2³ = 2121111211213 is a prime.

It is a super-2 number, since 2×2121111211221² (a number of 25 digits) contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2121111211194 and 2121111211203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121111211321) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3784755 + ... + 4308896.

It is an arithmetic number, because the mean of its divisors is an integer number (131276337556).

Almost surely, 2^{2121111211221} is an apocalyptic number.

It is an amenable number.

2121111211221 is a deficient number, since it is larger than the sum of its proper divisors (1029520890123).

2121111211221 is a wasteful number, since it uses less digits than its factorization.

2121111211221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8094481 (or 8094478 counting only the distinct ones).

The product of its digits is 32, while the sum is 18.

Adding to 2121111211221 its reverse (1221121111212), we get a palindrome (3342232322433).

It can be divided in two parts, 2121111 and 211221, that added together give a palindrome (2332332).

The spelling of 2121111211221 in words is "two trillion, one hundred twenty-one billion, one hundred eleven million, two hundred eleven thousand, two hundred twenty-one".